[tomb]

Quote:

Originally Posted by ruZZ.il /img/forum/go_quote.gif well, I had to glue the tube socket sides back together cause they're about next to go in 'had' to, cause I found the epoxy

Oh yeah - duh! I forgot about that!

 

[ruZZ.il]

a miniMAX lives!

After some head scratching, wondering why my measurements made no sense, I jumpered RB8/9, biased it all up perfectly, and enjoyed the music

I didn't really have the time to build this just yet, but did it anyway

I'll get around to impressions and measurements next week and maybe some photos during the w.end. Other than a dead LED and a lifted pad trying to get it out, it's a perfect little MAX, but those can be fixed. There were hardly a handful of details I came across that need to get sorted out for the production board, mostly just silk screening adjustments and synchronizing the BOM and the board. The effort that was put into this shows. Thank you Pete, Thank you Colin, thank you Tom!

 

[amphead]

That's awesome Russ! Let us know how it sounds.

 

[ruZZ.il]

well my very first brief impression was kinda groggy but when the tubes had been on for a bit and I'd upped the bias even to just 41ma over 30, things are already smoother, better bass, but still lacking some detail that I expect to crack in. Its a can't miss #1 sans the vit Qs (I'll stick them in a little later, with some tubing) so I'm pretty familiar with what its going to sound like, with already promising outcome

Was cool meeting you Ron!

 

[ruZZ.il]

Still need to fix the LED and add the Vit Q. bypasses..

 

[tomb]

Quote:

Originally Posted by ruZZ.il /img/forum/go_quote.gif Still need to fix the LED and add the Vit Q. bypasses..

Let's put our heads together on installing the VitQ's. Things are much tighter than Colin and I had counted on. Max Hester had problems with the VitQ
s first, but now I'm having the same issue. I've built mine except for putting the VitQ's in there and boy, is it tight. The pads aren't exactly far enough apart to allow a good kneeling position, either (the top of the cap is too high). I noted in Max's Mini, he kneeled them on one end and then nestled the lead on the high side inbetween the fins on the middle sinks. That's probably not a good idea for the long-term without some teflon tubing protection, but I was hoping we could make it without.

I tried the 0.22uf K42's and they're too fat to fit between the back of the pot and the front of the right channel CA7 cap. So, it's the VitQ's somehow or back to Wima's.

I'm thinking if we add some extra pads to the outside, that may give us enough room to kneel the VitQ's without the lead on the other end hitting the middle sinks.

Tell us what you think when you try it.

 

[Beefy]

Quote:

Originally Posted by ruZZ.il /img/forum/go_quote.gif Still need to fix the LED and add the Vit Q. bypasses..

Looking fantastic!

*

I'm currently building up a Mouser BOM for one, maybe two of these babies. I'm thinking both will be Blackgate/VitQ builds, with one being an experimental MOSFET build, the other BJT. I'm using my previous BOM as a template, but coming up with a couple of inconsistencies. Any advice from tomb or other prototype builders would be appreciated, as I'd like to get some other goodies for my Buffalo DAC in the next couple of weeks.

Oh, and sincere apologies if these have already been answered. I'm a bit too frazzled right now to go through the thread and actually absorb any of it.....

CR5 has been deleted?
CM2 has been deleted?
CM3 is now 470µF? This controls the delay, so I assume that 330µF is still OK?
Any word yet on RR4? I'm happy to buy multiple options now and install later.
Part number for the tip jacks?
RCA jacks will definitely be available at Beezar?
The Mini MAX output stage seems to be a 100% complete translation of the regular MAX. So can I assume that the MOSFET output stage will translate 100% as well? That if I follow the MOSFET max BOM, I shouldn't be missing any parts?

I think that is all for now. Cheers everyone!

*

[EDIT]
Quote:

Originally Posted by tomb /img/forum/go_quote.gif That's probably not a good idea for the long-term without some teflon tubing protection, but I was hoping we could make it without.

Is it too hot there on the heatsink to just use heatshrink?

 

[ruZZ.il]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif ....he kneeled them on one end and then nestled the lead on the high side inbetween the fins on the middle sinks. ....some teflon tubing protection....

Thats pretty much what I was thinking of doing. I was waiting till I got back home where I have some teflon tubing..

The left side is less of an issue, since it can just lay on top of the headphone jack, perpendicular to it.. this would mean having a longer signal path.. most likely negligible.

I was going for the kneeling with teflon on both sides for symmetry.. mosltly visual.

....It may just have to be that way.
I can think of other, less viable methods though:

1. Laying the output electrolytics down and placing the vit Q's above them, perpendicular to them, in between the heat sinks. (this actually doesnt sound too bad... maybe you can try it out if you haven't soldered those in yet)

2. adjusting the layout drastically, pushing the ccs aside, the electrolytics back, and positioning the vit Q between the heat sinks.. BZZZZT.

 

[tomb]

OK - I've got a creative bend that allows the VitQ to kneel to the outside without the end nipple getting too close to the outside sink. I actually moved the outside lead to the next closest middle pad, not the one on the outside. With a Z-bend that wraps around and under the end of the cap, that lets it sit on the board without the bend at the nipple touching the outside sink. It works the same for the middle sink, but that one is easy to see (high side of the cap). Plus, it's under 1".

We have a solution - I'll draw up a template when I get a chance. It's just a single Z-bend underneath on the outside.

Beefy - I'll have to answer some of that post tomorrow, when I get a chance (in about 7 hours). It's already past my bedtime on a work night.

For now, though:

Quote:

CR5 has been deleted?

Yes.
Quote:

CM2 has been deleted?

Yes.
Quote:

CM3 is now 470µF? This controls the delay, so I assume that 330µF is still OK?

Yes. We prefer 470uf. It gives a fairly long delay (45sec?), but it cuts down on the danger if you happen to bump it on-off-on within a few minutes time. The delay can be 1/2 half as long in that case. If it gets below ~10 seconds, that's entering the danger zone.
Quote:

Any word yet on RR4? I'm happy to buy multiple options now and install later.

Anything you can find that's in fractional ohms or less (<<1). I may have a firmer answer in a couple more days after I do some LNMP tests.
Quote:

Part number for the tip jacks?

This is on the MAX website under the construction section. I believe the data sheet is actually linked on the MOSFET-MAX template page, but I'll have to check later and give you those links for sure. I will add them to the BOM when I get a chance.
Quote:

RCA jacks will definitely be available at Beezar?

Yes. Fry's carries them as well, if I happen to run out (only temporary, if it happens). Other vendors may have them, too. They're Philmore MTG12.
Quote:

The Mini MAX output stage seems to be a 100% complete translation of the regular MAX. So can I assume that the MOSFET output stage will translate 100% as well? That if I follow the MOSFET max BOM, I shouldn't be missing any parts?

Yes, that should be correct. You can always punt and purchase a Lansing with a tall top. That would let you use taller sinks. Taller Lansings are available in the "C" style, but they're 2.5" tall. We won't be machining that style/size, though.

 

[Beefy]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif Beefy - I'll have to answer some of that post tomorrow, when I get a chance (in about 7 hours). It's already past my bedtime on a work night. For now, though:

That pretty much answers everything - love your work

Quote:

Yes, that should be correct. You can always punt and purchase a Lansing with a tall top. That would let you use taller sinks. Taller Lansings are available in the "C" style, but they're 2.5" tall. We won't be machining that style/size, though.

I am still aiming for your pre-machined case with 1" heatsinks and MOSFETS. Realistically, I think that this combo will be better cooled than most regular MAXes in unventilated Hammond enclosures. I won't be able to open the MOSFETs right up, but I think it will still be a good option over any BJT combo.

But there is only way for me to find out - by actually building it - and I plan to do exactly that

 

[tomb]

Quote:

Originally Posted by Beefy /img/forum/go_quote.gif That pretty much answers everything - love your work I am still aiming for your pre-machined case with 1" heatsinks and MOSFETS. Realistically, I think that this combo will be better cooled than most regular MAXes in unventilated Hammond enclosures. I won't be able to open the MOSFETs right up, but I think it will still be a good option over any BJT combo. But there is only way for me to find out - by actually building it - and I plan to do exactly that

Tip Jacks are Mouser #530-105-0801-1. (The part # will vary, depending on what color you pick.)

Also, don't forget that we're using axial Schottky's - the MBR360 - for the rectifiers in the back. This is important, because the tip jack and rear panel layout won't work with TO-220-style rectifiers. It's really a tight fit on the proto board. If you don't bend those leads as close to the package as possible and as close to 90 degrees as possible, they won't fit in. Colin has said he's loosened up the holes and lead spacing a bit on the production design, I believe.

 

[Beefy]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif Tip Jacks are Mouser #530-105-0801-1. Also, don't forget that we're using axial Schottky's

I already had the rectifiers covered, but good call.

So my BOM is pretty much complete now, and I'll place my Mouser order in a few days. Still need to decide how I'm going to get hold of some Black Gates though. There are *none* in Australia

 

[tomb]

Quote:

Originally Posted by ruZZ.il /img/forum/go_quote.gif Still need to fix the LED and add the Vit Q. bypasses..

I meant to say this looks great, Russ! Did you have trouble getting those MBR360's in? I had to work at it for awhile, but got them in and flush.

You guys using all these Black Gates are making me feel substandard with my ES's.

 

[ruZZ.il]

Thanks!

The diodes were a bit of a tight fit, but I wouldn't really say they're a problem.. just an extra few minutes. I put the diode on the table, push and bend. It gets the leads pretty close to how they have to be. just a few small adjustments after that and they fit in with a little push. I pre-snipped too so once the bends were right it just fit in and stayed in, so soldering was easy. my fingers hurt just a little from the bending though

I must say, Mario Kart wii sounds fantastic through this amp!

 

[Beefy]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif You guys using all these Black Gates are making me feel substandard with my ES's.

You know what? I say screw Black Gates. There are none in Australia at all, and I'm not paying $53 per amp plus shipping from Michael Percy

That money could buy me a LOT of beer, and various other substances that will allow me to enjoy the music even more. ES's will do juuuuuuuust fine!